Project Fifteen
by whackybiscuit
Summary: In an attempt to replicate Ichigo's powers, Mayuri clones him. But when the clone seemingly dies, he gives up. Unfortunately, things aren't as apparent as they seem... IchigoXOC!
1. Chapter 1

**Disclaimer: I don't own Bleach.**

 _Project Fifteen_

 _Chapter One: Project Failure_

 _ **Shortly after the Thousand Year Blood War  
**_ **Squad 12; R &D**

Mayuri stood in front of the vat, watching with intrigue as white liquid filled the container. Multiple tubes pumped chemicals into the vat. "Very good…" he said quietly as a mass began to form inside the vat.

Walking over to the computer monitoring the vat, Mayuri hit some keys and checked the status of his experiment. The readout on the monitor told him that things were going swimmingly. On an adjacent screen was a diagram of a DNA strand, the source of his experiment. Next to the DNA there was a picture of a certain Substitute Soul Reaper. Mayuri tapped the screen and the DNA broke into several pieces, each signifying certain elements of the boy's genetics.

Tearing himself away from the monitory, Mayuri returned to his vigilance in front of the vat. A human skeleton was forming among the liquid as more chemicals are injected into the vat.

The scientist's ears perked when he heard the door open behind him. "How many times do I have to tell you? I am NOT to be disturbed when I'm in the middle of my experiment! This is too important to be interrupted!"

"Sorry. Nobody answered when I knocked so I let myself in."

Whirling around, Mayuri glared with venomous eyes when he saw Kisuke Urahara saunter into his lab. "What are you doing here?" His eyes glanced over to the subject in the vat worriedly. "How did you get in here in the first place?"

Kisuke, the marks on his face from restoring his eyesight still evident on his face, reached into the pocket of his robe and pulled out a keyring. "You know, for all your technological breakthroughs, you never bothered to change the locks in a hundred years."

"Hmph! I forgot you still had the keys…"

Walking up next to his old comrade, Kisuke crossed his arms and glared at the man while inspecting his specimen. "You seriously didn't think your experiment would escape my notice? This is a serious violation of Ichigo's privacy, you know," he scolded his former subordinate.

"Hmph!" The mad scientist turned away and put a hand on the glass vat, watching as his experiment took shape. "His privacy means nothing to me. I've put in too much effort into Project Fifteen to let something like privacy stop me."

Kisuke's scowl deepened. "And what do you think he's going to do when he finds out _you're trying to_ _clone him?!_ " Turning back to Project Fifteen, Kisuke saw the clone version of Ichigo Kurosaki take shape, the clone's orange hair prominent in the white matter that obscured most of its body.

Snickering, Mayuri looked at Kisuke with inquisitive eyes. "Oh please, Kisuke. Certainly you've thought of the same idea," he countered. "The prospect of taking Ichigo's power and replicating it?"

Scratching the stubble on his chin, Kisuke continued to look at Project Fifteen. He noted the tubes pumping chemicals into the vat and quickly surmised what he was giving the clone. "You're giving it Hollow matter and Quincy blood?"

"Along with Soul Reaper spirit energy and his own Human DNA," Mayuri finished. "The chemicals create the white bonding matter and constructs the clone's body piece by piece. When it's finished, I'll have my own Substitute Soul Reaper to toy with."

Kisuke's scowl deepened at the notion. He didn't know if Mayuri was simply acting on a long-standing fantasy of his or if he was just so rattled by the death of Nemu that he had gone off a very deep end. He couldn't deny that replicating Ichigo's power was an idea he'd thought about multiple times but there were multiple concerns along that line of though. "What purpose would you need to clone Ichigo?" he asked, although he knew it didn't matter what excuse Mayuri gave; he was still crazy.

"You've seen the boy's bountiful power," Mayuri pointed out, back at his monitor and hitting keys. "You yourself trained Ichigo Kurosaki. Imagine if the Soul Society had that kind of power at our disposal whenever there was a crisis?" he suggested.

"Is that what you plan on telling the Head-Captain when he finds out what you've been doing?"

"I'm certain that our new Head-Captain will appreciate the advantages of having such a powerful asset at our beck and call instead of hoping that the impudent whelp will come and save us when he deigns to show up."

"Mayuri, that's not fair and you know it."

Mayuri looked up and glared. "Maybe so, but it still does not change facts. Besides…" his lips formed a sinister sneer. "I promised Ichigo that I would repay him for his insult back in Hueco Mundo. If I can't do it to his real body then I'll settle for a clone."

Hearing movement from inside the vat, Kisuke turned to see Project Fifteen's eyes slowly open up. "Mayuri, can it see us?" he asked. "Does it know who we are if it's Ichigo's clone?"

"Its optical and audible senses have not fully developed yet. The infusion of Ichigo Kurosaki's original DNA should be able to transmit some of his memories into the clone through the incubation matter."

"Um…Mayuri? I don't think DNA works like that…"

"Shut up! I know what I'm doing!" Mayuri yelled. "This saves me the trouble to trying to teach it from scratch."

After a few moments of waiting quietly, Kisuke's expression turned grave. "Mayuri, you said that the clone can't hear or see anything, right?"

"Yes."

"Can it feel?"

"No, why?"

"Because it looks like it's in agonizing pain."

Looking up, Mayuri's eyes widened in horror as the clone started writhing in pain. "NO!" he shouted, typing keys on the computer. "Something's gone wrong! The clone's body is breaking down!" Examining the data, Mayuri came to a grave conclusion. "It's rejecting the incubation matter!"

Kisuke had seen many horrors during his stint as a captain. But seeing the sight of Ichigo Kurosaki's in agonizing pain while its body was torn apart was a sight he wished never to see. "Let it out!" he told the captain. "It'll die if it remains in there!"

Cursing his misfortune, Mayuri slammed his palm on the big red button and stopped the experiment. The tubes detached themselves from the tank, spewing blood and white matter onto the floor. "Dammit! Dammit! DAMMIT!" he cursed over and over again as he tried to save his experiment. He hit a switch and opened the vat. "Pull it out of there!"

Kisuke stood aside as a cascade of amniotic fluid and incubation white matter splashed onto the floor. He reached for the dying clone but Project Fifteen's hand dissolved in his grasp. "It's too late…" he said mournfully.

All Mayuri could do was watch as his precious clone disintegrated into the white matter, the goo bubbling up and forming a great big clump on the floor. "GODDAMMIT!" he shrieked. "WHY?!"

"It's for the best," Kisuke told him. "At least it was quick."

"Don't patronize me!" Mayuri huffed, sitting down in the chair. He looked at the white mass on the floor and scowled. "What made the clone reject the bonding matter? It's his own DNA for crying out loud!" Sighing, he got up. "I'll go fetch the mop."

"Want me to get a bucket?"

"Oh shut up! Get out of my laboratory!"

"Actually, it's my lab."

"I don't see your name on it!"

Kisuke pointed up. Mayuri looked up at the ceiling and saw something scribbled at the corner. " _This lab is property of Kisuke Urahara! Hiyori, stay out of my cupcakes!"_

"I hate you…" he grumbled as he exited the lab, Kisuke following behind him.

The door closed, filling the empty lab with silence. Had the two men stayed, they would have noticed that the white matter was beginning to bubble and swell. Taking the DNA of the failed clone, the incubation goo began to reshape it in a more suitable form.

As minutes ticked by the goo began to grow like a balloon, life being breathed into the creature within. First a skeleton was formed, then organs, then muscles and tendons and finally skin was wrapped around the unknown creature. The white cocoon pulsed as its heart took its first beat. Air filled its lungs, awakening its consciousness. Amidst the sea of white, a clear image filled its vision. An image of Ichigo Kurosaki. The white matter told it who this person was. It filled the creature with knowledge of the Substitute Soul Reaper's life and his abilities.

But more importantly, it told the creature where to find Ichigo.

As it became fully formed, Project Fifteen began to feel claustrophobic. It had to escape. It had to get out of here.

The white cocoon burst open and a figure tumbled onto the cold floor. Naked and clawing at the ground from its new sense of touch, Project Fifteen opened its brown eyes, a head full of orange hair sprawling down its back. Turning its head, the finished clone looked at the picture on the screen and recognized itself.

"Ichigo Kurosaki…"

To be continued


	2. Chapter 2

_Chapter Two: Face to Face_

 **Ichigo's House**

The Substitute and his friends were having a much needed rest, chilling at Ichigo's house for some rest and relaxation after the war with the Vandenreich. Ichigo and Orihime especially were taking it easy, having sustained terrible injuries at the hands of Yhwach.

Ichigo and Chad sat on the couch while Uryu sat in a nearby chair. Orihime was with Yuzu in the kitchen making tea for the group.

Slumping back against the couch, Ichigo sighed as a familiar jolt of pain hit him. Because Orihime was badly hurt, she wasn't able to heal Ichigo, leaving his treatment to Rukia. Though the lieutenant was able to treat his wounds, there was unfortunately a shadow of pain, an echo that left itself as a reminder of when he almost gave up the fight. Turning his head, he looked over at Chad, the only one of the four to make it out of the conflict unscathed. "How're you holding up, Chad?"

His friend gave him an assuring smile. "I'm doing fine, Ichigo. I'm just glad everyone made it out okay."

Uryu pushed up his glasses. "Hopefully with Yhwach dead, we can finally get back to our normal lives. Chad, you mentioned earlier that you were thinking of going into sports?"

"Yeah," Chad looked down his hands. "I decided to go into boxing. I'm proud of my hands. I think I could do pretty good as a boxer."

"Tea's ready!"

The three boys turned to see Orihime walk into the room, carrying a tray with four cups of tea. "Here you go! Yuzu and I just finished."

Ichigo took a cup and eyed it suspiciously. He liked Orihime but was always on guard whenever she cooked anything, even with his sister's involvement.

 _Ding-Dong!_

Taking his way from the suspicious tea, Ichigo set down the cup and stood up. "I'll get it." His father was busy in his clinic and Karin was still at her soccer practice. Not wanting to bother his sister, Yuzu, he walked to the doorway.

 _Ding-Dong!_

"Hang on! I'm coming!" Ichigo shouted annoyingly. He unlocked the door and opened it. "Rukia? Renji?"

The two lieutenants smiled at their friend with their Gigais. Renji was wearing a black shirt with Kisuke's hat on it with jeans while Rukia opted to wear a white blouse. "Hey, Ichigo. Mind if we come inside?" Renji asked.

"Sure, come in."

Ichigo's friends welcomed the pair as they entered the living room, Orihime giving Rukia a warm hug. As everyone got settled in, Ichigo asked the obvious question. "So what brings you here? Is there a problem in the Soul Society?"

Thankfully the pair shook their heads. "No, everyone is still trying to sum up the damage in the Seireitei. The Head-Captain's busy trying to get a headcount of the fallen. It'll be a while before things get back to normal. We haven't even started to rebuild yet," said Rukia

Renji spoke up. "Captain Kuchiki sent us. Apparently there was an incident at Squad 12 the other day. We were sent here to investigate."

Uryu looked perplexed. "Investigate what? Is it the Vandenreich?" He'd overheard what Mayuri was doing with some of the Sternritter and it rankled him that the scientist was continuing more experiments on the Quincies, even if they were his enemies.

"We don't know," Rukia told him. "It all began when Third-Seat Akon noticed something odd…"

 _On Mayuri's orders, Akon went into the Squad's storehouse in order to find more supplies for a new experiment of his. He assumed he simply needed new clothes for when Mayuri grew the next Nemuri after Nemu was brutally slain by Pernida. Reaching the storehouse interior, Akon soon became aware that something was wrong. The door had been cut to ribbons and there were footprints everywhere, stained not with water or any liquid Akon was aware of, but of a strange white matter._

 _Squatting in the doorway, Akon examined the nearest footprint. His inquisitive mind raced as he struggled to piece together who or what made it. His mind initially thought it was one of the Sternritter that escaped the aftermath of the war. But he quickly dismissed it. All of the Sternritter had been accounted for, their bodies now officially Mayuri's property. Examining it further, he couldn't quite make out what it was. The white matter surrounding it made the details more muddled._

 _Heading deeper into the room, Akon looked around to see what had been disturbed. It was clear to him that whoever came in here was no longer around. The footprints leading to a broken window attested to that theory. Looking through the boxes that had been haphazardly opened and discarded, Akon quickly found several missing items: in a box full of discarded Shihakushos, Akon did a count and found that the box was short one uniform. Amidst the other stolen items included a pair of Tabi socks and sandals, some food and a map of the Seireitei._

 _"I'd better inform the captains," he said before leaving, though not before getting what he came for. An intruder was bad enough. But he wouldn't dare forget his captain's items and risk his wrath._

Listening to Renji's story, Chad spoke up. "So why are you here? You said that it was a map of the Seireitei that was stolen."

"Well, Akon first thought it was a rogue Quincy. Maybe one of their foot soldiers. But then the communications department that was monitoring the Senkaimon flagged an illegal entry. Someone stole one of the Hell Butterflies and used it to guide themselves to the World of the Living."

"Who was it?"

 _Nanao entered the Soul Society's communications section. She had come at Kyoraku's request after one of the messengers told her that there was a situation. "What is going on?" she asked as she walked up to one of the men at the monitors._

 _"We were alerted to an unauthorized use of the Senkaimon, Lieutenant."_

 _Nanao frowned behind her glasses. "What of the guards? How did they let an intruder through?"_

 _"We've sent several men to investigate. They found the guards all unconscious. They have yet to regain consciousness. We're bringing up the data now."_

 _A picture popped up on the monitor. Nanao leaned down to get a better look. Inside the dark Precipice World, a figure hurried through the path, guided by a Hell Butterfly, obviously stolen. Unfortunately she couldn't tell who the miscreant was. The figure wore a hood over their head. There was something on their back but it was bundled up and obscured from view._

 _"Do we know where they're going?"_

 _Hitting a few buttons, the man found the trespasser's destination. "They're heading for…Karakura Town!"_

 _Nanao paled. Was it a rogue Quincy? Out for revenge on Ichigo for killing Yhwach? "We need to alert the others. Wait…" she leaned closer when she saw something strange. "Zoom in there, on their face." When the assistant did so, she noticed an odd detail. While the hood obscured most of the face excluding the mouth, she did noticed a startling feature. "Long…orange hair?"_

All eyes turned to Orihime. The girl gasped in surprise and put her hands up defensively. "It wasn't me! I haven't been to the Soul Society since we got back! I'd never hurt anyone!"

Rukia merely chuckled. "We know, Orihime. Besides, you don't have a sword. The guards at the Senkaimon said they were attacked by a hooded figure armed with a blade."

"Did they see who it was?" Ichigo asked curiously. "What was their weapon? A zanpakuto?"

"We don't know. They said they were all knocked unconscious before they saw the trespasser use their weapon. Whoever it was, they're fast."

Renji finished the story. "Head-Captain Kyoraku was worried that someone was targeting Ichigo, so he sent us to investigate and to keep you safe while you're recovering."

"Hey! I'm just fine! And besides, you two got banged up pretty bad too!"

Rukia put a hand on her friend's shoulder to stop them from arguing. "That's enough. We're all not in the best condition. But then again, nobody else is, either. But we wanted to come to make sure you guys were safe, Ichigo."

"Aww!" Orihime fawned. "Thanks, Rukia!"

No sooner did the pair finish their explanation did their phones go off. "Hollows?" Ichigo asked as they flipped their phones open. When he saw their faces turn sour he knew that something was up. "What is it?"

Uryu's finely tuned senses picked up the problem before Rukia could explain. "Hollows! And lots of them." He suddenly stood up and looked out the window. In the distance he could see a Garganta start to tear its way through the sky.

Putting her phone away, Rukia nodded. "Ever since the war with the Vandenreich left us with so few men left, the Hollows had been entering the World of the Living in droves. They want to turn the Human world into a buffet before the Thirteen Court Guard Squads get back on their feet."

Ichigo was already in his Soul Reaper form, having pushed himself out of his body with his combat pass and letting it sink back into the chair. "Then we have no time to waste!"

"What about the intruder?" Orihime asked concerned.

"It'll have to wait. Our first priority is protecting Karakura Town. Besides, if the intruder is after you guys, then it's for the best if we're closer to you."

Opening the window, Ichigo charged at the window and headed for the encroaching Garganta, followed by his five friends.

Unbeknownst to Ichigo or the others, they were being watched. Outside the Kurosaki house, crouched in the shadows, a hooded figure looked at the team as they left to fight Hollows. The figure's eyes laid squarely on the Substitute Soul Reaper, recognizing him from the images its birthing matter fed it.

"Ichigo…Kurosaki…" it said, tasting the name in its mouth. Gripping the weapon on its hip, the figure leapt out of the shadows and followed the group, taking care to lag behind enough to make sure they didn't realize that the experiment was following them.

 _ **Sometime later…**_

"Huh, you know…I thought this'd be harder," Ichigo said as he cut down another Hollow with ease, his longsword slicing through its mask.

Chad crushed one Hollow with his master fist before blasting another. "We have gone through a lot since you became a Soul Reaper."

"He's right." Uryu unleashed a volley and destroyed several Hollows at once. "Between the Soul Society, the Espadas, Aizen and the Vandenreich we've grown exponentially. Even a hoard of Hollows like this feels trivial after all that."

The group made it to the Garganta just as massive hoard of Hollows descended on the town. What the hungry creatures were not expecting, however, was the team of Soul Reapers and Humans waiting for it. Fighting on top of a wide rooftop, Ichigo and his friends went to work and engaged the Hollows. Even though they were recovering from their injuries, minus Uryu since he healed himself by transferring his wounds to Haschwalth, Ichigo and his friends were still more than capable to fight simple Hollows.

Out of the Garganta emerged a massive snake-like Hollow. The monster hissed at the pair and shivered, its scales bristling before erupting from its body. "Whoa!" Orihime cried out before protecting everyone with her shield. The scales bounced off the shield and landed on the ground, littering the rooftop with countless white scales. Chad charged past the shield and fired an El Directo at the Hollow. The Hollow was unable to dodge and was obliterated.

"Nice save, Orihime!" Rukia praised.

"Thanks!" Orihime giggled back before noticing the scales were starting to move. "Guys! Look!"

Everyone watched as the scales came to life, forming a whole army of small insectoid Hollows. "Looks like we're not out of the woods yet," Ichigo said, quickly drawing his shortsword.

"So let's cut the down!" Renji held his sword up and unleashed his Shikai. "Roar: Zabimaru!" His whip-blade slashed at the nearest insect Hollow, cutting it in half. "They may outnumber us but they're still Hollows. Cut them down!"

"Right!"

Rukia took a stance. "Dance: Sode no Shirayuki!" Her sword transformed into its more beautiful form. "Tsukishiro!" She jumped away from a group of insects as they lunged for her, the area where she was standing lighting up in a bright circle and freezing them into oblivion.

Chad found himself surround on all sides. Slamming his fists together, he called upon the full power of his Fullbring. "Brazo Derecho Del Gigante. Brazo Izquierda Del Diablo." Bring up his shield, he swatted away one of the attacking creatures before destroying it with a blast, repeating this process over and over.

Orihime saw a trio of insect Hollows coming right at her. "Koten Zanshun! I Reject!" She summoned Tsubaki and sent him whirling towards them, cutting them to ribbons. Hearing sounds behind her, she found more of them trying to flank her and readied her hairpins again. "Santen Kesshun!" She blocked one of the Hollows strikes and sent Tsubaki to destroy them again.

Taking to the air with Hirenkyaku, Uryu summoned his new bow and picked them off one by one. He was taken aback when he saw five of the Hollow slam themselves together to fuse into a hideous bigger insectoid. "So they can merge together. That must be how that bigger Hollow can reproduce. We'd better destroy them all before it can come back." He fired another volley and destroyed the bigger insectoid before it could grow further.

The hotheaded Renji and Ichigo were working together, cutting down the creatures one after the other. "Think that thing's the last of the Hollows to come through?" Ichigo asked as he chopped one in half.

"How should I know? Just focus on destroying the ones here. We'll get Kisuke to deal with the Garganta after this." He hurled Zabimaru at another Hollow and cut through it. "There, that's the last one."

After defeating the hoard, the six reconvened. "Looks like that's that," Ichigo smiled as he put away his swords.

"Looks like it. We'll have to be on guard for a while though. Like we said, more and more Hollows are coming in hoards to try to get the jump on the Soul Reapers," Rukia said before sealing her sword.

While the group was celebrating their victory, they didn't realize that one last insectoid Hollow still remained, hiding in the shadow of a water tower. Looking over at the group, it noticed the Human with the strange arms off its guard and prepared itself. Knowing it wouldn't get a better chance, the Hollow jumped from its hiding spot and aimed its sharp appendages at Chad's back.

Ichigo saw the white blur out of the corner in his eye and gasped. "Chad!" He reached for his shortsword. "Behind-"

"Getsuga Tensho!"

Out of nowhere came a crescent-shaped beam of energy that intercepted the Hollow, obliterating it into atoms. Everyone immediately drew their weapons in alarm and looked around. "That…that was a Getsuga Tensho!" Orihime gasped, confused as everyone else. "But Ichigo was standing right here!"

Looking around, Rukia saw a figure on a nearby rooftop and pointed. "I believe we found our intruder."

Ichigo gripped his sword tighter as the figure came into his view. The mystery intruder wore a plain Shihakusho with a wide black hood that obscured their face. His confusion grew, however, when he saw what the person was holding in their hand. "That's…"

"That's Ichigo's Zangetsu blade!" Uryu exclaimed.

All eyes turned to the sword in Ichigo's hand and back to the intruder's. It was an exact copy of Ichigo's shortsword. "But how?!" Chad gasped. "Is it a Reigai?"

"No. Kageroza never created a Reigai of Ichigo because he couldn't replicate Ichigo's spirit energy," Rukia reminded. Her eyes narrowed as she got a better look at the intruder. Like everyone else she initially thought it was a Reigai. ' _But this person is thinner than Ichigo.'_

Uryu likewise caught a similar detail. ' _This person's spirit energy feels similar to Ichigo's but something feels…off. What is he? Wait…"_ His sharp eyes saw something else. ' _The intruder's hands. They're more…slender like Rukia's or Orihime's. A woman?'_

Renji stepped forward and pointed Zabimaru at the stranger. "Identify yourself! Who are you? Why did you trespass through the Senkaimon?!" he demanded with authority.

The stranger looked from person to person until their eyes rested on a certain Substitute Soul Reaper. "Ichigo Kurosaki…" it said in a low voice.

Everyone jumped in surprise when the figure Flashstepped over to the rooftop and calmly walked over to them. Renji and Rukia immeideatly put themselves between the stranger and Ichigo. "Why are you after Ichigo?" Rukia demanded. "Why do you have his Zangetsu?"

"Zan…getsu?" it repeated, looking down at the blade in its hands. "Is that…what this is? Everything…is muddled…"

Too confused by the stranger's actions, Ichigo pushed past his friends and stood in front of the stranger. "That's enough! Who are you?"

"Ichigo…Kurosaki."

"Yes, I'm Ichigo Kurosaki." Getting agitated, Ichigo grabbed the stranger's hood and pulled it up. "Now who the hell…are…you?" Ichigo's voice trailed off and his eyes widened to their limit when he got a look at the person's face. Everyone gasped at the same time when they finally say who had joined them.

Ichigo was looking at…himself…as a woman!

Standing a few inches shorter than the original, the experiment looked like what Ichigo would have become if he'd been born the opposite gender. Her long orange hair trailed down her shoulders while she stared at him with dark brown eyes. Up close, Ichigo could see that the girl was slender than him, her chest just as big as Orihime's. Looking at the object on her back, everyone realized that it was the same wrapped up Zangetsu longsword that Ichigo had.

"What…" Ichigo stumbled backwards, the shock more than he could bear. "What are you?!"

The experiment put a hand to her chest before pointing at him.

"I'm you. I'm Ichigo Kurosaki."

To be continued

 **A.N.: Sorry for the long delay. Will try to update more frequently. As always please R &R. **


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